Decorative pulsating flame incandescent lamp



J. F. ENGLISH 3,384,774

DECORATIVE PULSATING FLAME INCANDESCENT LAMP May 21, 1968 Filed July 9,1965 CONTAINS IODINE OR METALLIC IODIDE IN LARGE AMOUNT lnven tor'.damesFEn Lish b5 @626 United States Patent 3,384,774 DECORATIVEPULSATING FLAME INCANDESCENT LAMP James F. English, Lakewood, Ohio,assignor to General Electric Company, a corporation of New York FiledJuly 9, 1965, Ser. No. 470,781 8 Claims. (Cl. 313-222) ABSTRACT OF THEDISCLOSURE A luminous pulsating colored flame effect is produced by avertically oriented tubular incandescent lamp containing a large amountof elemental iodine or vapor of various metallic iodides.

This invention relates generally to electric incandescent lampscomprising a sealed envelope containing an incandescible filament, andhas as its principal object the provision of a decorative lampcharacterized by the presence of a luminous pulsating colored flameeffect.

I have discovered that when an essentally tubular lamp envelopecontaining an incandescible filament is provided with an atmospherecomprising vapor of various metallic halides or a large amount ofelemental iodine at unusually high pressure, and is oriented with thetubular envelope in a vertical position, or at least tilted appreciablyfrom the horizontal, and with at least a significant part of thefilament at the lower end of the envelope, upon energization of thefilament a luminous pulsating colored flame effect appears in theenvelope.

Further features and advantages of the invention will appear from thefollowing detailed description of species thereof and from the drawingwherein: FIGS. 1 to 3 are vertical elevations of different forms of lampcomprising the invention.

Referring to FIG. 1 of the drawing, the lamp illustrated thereincomprises a tubular bulb or envelope 1 of vitreous material, preferablyquartz (fused silica) or a heat resistant glass of relatively highsoftening point. The bulb contains a filament 2, preferably of tungstenwire which may be helically coiled throughout its length, as indicatedin the drawing, or which, for smaller wattage sizes, may be helicallycoiled for a short distance at its lower end (as shown in full lines inFIG. 1) and extend as a relatively straight Wire to the upper end of theenvelope. The filament 2 is connected at each end to a lead-in conductor3 which has a portion thereof hermetically sealed in a flattened pinchseal portion 4 at each end of the envelope. When the envelope 1 is madeof quartz, the lead-in conductor preferably comprises a thin foilportion 5 which is hermetically sealed in the pinch portion 4, an outerportion 6 ofmolybdenum wire, and an inner portion 7 preferably oftungsten Wire. When desired, the separate inner wire portion 7 may beomitted and a straightened wire leg portion of the filament wire 2 maybe extended into the pinch seal 4 where it is welded to the foil portion5. Also, when needed, the filament 2 is additionally supported from theenvelope Wall by auxiliary support members engaging the filament atspaced points along its length, as is well known in the art.

In the form shown in FIG. 2, the elongated tubular envelope 1a is joinedto and closed at its lower end by a short transverse tube portion 8which contains the coiled filament 2a at the bottom of the tubularenvelope 1a. The filament 2a is connected to lead-in conductors 3a whichare sealed through pinch seal portions 4a at the ends of the transversetube portion 8. The envelope 1a is sealed or tipped off at its upper endby the sealed residue of an exhaust tube 9 through which the envelope isevacuated and filled with the desired atmosphere.

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In FIG. 3, the envelope 1b has a single pinch seal 4b at the bottomthereof in which are sealed both the lead-in conductors 3b. The coiledfilament 2b is located at the bottom of the envelope 1b and has legportions thereof extending into the pinch 4b and welded to the foilportions 5b of the lead-in conductors.

In a particular embodiment, a lamp of the form shown in FIG. 1, havingan envelope 1 of about 10 mm. outside diameter, an overall length,including the pinch seals 4, of about mm., and a helically coiledtungsten wire filament 2 designed to consume about 500 watts at volts,was evacuated and supplied with 0.2 gram of mercuric iodide. In thiscase, no fill gas was added to the envelope. Upon energization of thefilament 2 at voltages as low as about 80 and up to 120 volts, luminouspulsating flames surround the region between the filament and theenvelope, as indicated by the flame shape shown at 10. This reactiongoes on indefinitely, and may be due to emission from the mercury andiodine atoms combining I after,v previous dissociation at the hightemperature filament.

When the lamp is positioned horizontally, the turbulence disappears, andan orange luminous column exists through which the filament is notvisible. A slight tilt of a few degrees from the horizontal positioncauses a pulse to develop in the luminous column along the lamp axis.

The flame effect has also been produced in lamps containing iodides ofother elements such as zinc, titanium, germanium, tin, arsenic andantimony. There are slight differences in the color of the light emittedby the lamp. Arsenic, germanium and mercury iodides all produce a ratherred-orange emission. Antimony and thin iodides are similar and less red,i.e., more yellow-white. Titanium iodide, on the other hand is evenredder. The color is partly determined by the amount of excess iodinepresent in the lamp.

The different iodides also produce flames having different rates ofmovement. For example, the mercury iodide flame appears to move quiterapidly compared to the others.

The flame effect may also be obtained with vapors of iodides of othermetals having a low dissociation energy, moderate vapor pressure andstrong absorption in the visible specturm. In some cases it may benecessary to adjust the total pressure with some suitable gas, such asargon or hydrogen, for example, to obtain the flame effect with otheriodides such as those of bismuth and lead, for example.

It has also been demonstrated that elemental iodine is equal to or insome respects better than iodides for producing the flame effect. Thehigher vapor pressure and lower boiling point are desirable inasmuch asthey permit a lower filament temperature during operation. However, inaccordance with the invention, and in contrast to the now conventionaliodine cycle illuminating lamp such as disclosed and claimed in Patent2,883,571 to Fridrich and Wiley, it is necessary to provide a muchgreater quantity of iodine; in fact the minimum amount of iodinerequired for this purpose is much greater than the maximum amount (about1 micromole per cc. of envelope volume) present in lamps of the typedisclosed in the said patent. The most effective amount of iodine isdependent upon envelope size and filament temperature; it is readilydetermined by simple trial in a lamp of given design. The upper limit isdetermined simply by the maximum gas pressure that the envelope canwithstand during operation. In a lamp of the form shown in FIG. 1 andproportioned as described above in connection with mercuric iodidefilling, a quantity of at least 50 milligrams of iodine may be placed inthe lamp having an envelope volume of about 3.5 cc., with or withoutadditional gas filling such as argon or hydrogen.

The flame effect is present in either a vacuum lamp, or one containing anonoxidizing gas. The flame effect has been observed for all pressuresup to about one atmosphere of either argon or hydrogen, or both,provided the iodine content is sufliciently high. Hydrogen, or a gaseousmixture containing hydrogen, has the advantage of in creased envelopewall temperature for a given filament voltage, thereby tending to avoidcondensation of iodine in the remote and cooler regions of the envelope,especially in lamp designs of the type shown in FIGS. 2 and 3.

In a lamp of the form shown in FIG. 2 and containing either elementaliodine or metallic iodide, with or without a supplementary gas filling,the filament 2a may be a coiled coil of tungsten wire designed foroperation at 200 watts with a current of 6.6 amperes, in an envelope 1aof mm. outside diameter and 50 mm. length, the transverse tube portion 8having a diameter of 10 mm. and an overall length, including the seals4a, of mm.

The lamp shown in FIG. 3 may have an envelope 1b of 10 mm. diameter and50 mm. overall length, and contain a helical filament coil 21) of fiveturns for operation at 8.5 volts with a power consumption of 60 watts.

It may be noted, particularly with lamps of the type shown in FIGS. 2and 3 Where the filament is located at the lower end only of theenvelope, that it is necessary that the envelope temperature besufliciently high at all points of its interior to at least keep theiodine molten so that it can run back down to the bottom of theenvelope. There must be no configuration providing a pocket, such as asignificant lateral extension, in which the iodine can collect andthereby deplete the effective vapor supply. Similarly, the envelope 1aor 1]) must not be so long that its temperature is so low that theiodine will condense and settle out in the upper end thereof.Accordingly, the interior envelope wall should have a minimumtemperature, at any point, at least above the melting point of iodine(i.e., above about 130 C.), and preferably above about 250 C. to insureproper operation, and the iodine content should be at least about 15milligrams per cubic centimeter of envelope volume, whether the iodineis present in elemental form only or as part of a metallic iodide suchas referred to above.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An electric incandescent lamp comprising a sealed envelope ofessentially tubular form adapted for orientation in a position inclinedfrom the horizontal during operation of the lamp, an incandesciblefiliment having at least a significant portion thereof located at thebase of said envelope, said envelope proportioned to attain a minimumtemperature at any area of its inner walls of about 250 C., and means tosupply in said envelope an atmosphere of the class consisting of vaporof elemental iodine and metallic iodides and mixtures thereof in anamount of at least about 15 milligrams iodine content per cc. ofenvelope volume and suflicient to produce a luminous pulsating coloredflame effect in the inclined envelope upon energization of the filament.

2. An electric incandescent lamp comprising a sealed envelope ofessentially tubular form adapted for orientation in a position inclinedfrom the horizontal during operation of the lamp, an incandesciblefilament having at least a significant portion thereof located at thebase of said envelope, said envelope proportioned to attain a minimumtemperature at any area of its inner walls of about 250 C., and means tosupply in said envelope an atmosphere of the class consisting of vaporof elemental iodine and iodide of at least one of the metals mercury,gold, zinc, tin, arsenic, antimony, bismuth and lead and mixturesthereof in an amount of at least about 15 milligrams iodine content percc. of envelope volume and sufficient in amount to produce a luminouspulsating colored flame effect in the inclined envelope uponenergizarion of the filament.

3. An electric incandescent lamp comprising a sealed envelope ofessentially tubular form adapted for orientation in a position inclinedfrom the horizontal during operation of the lamp, an incandesciblefilament having at least a significant portion thereof located at thebase of said envelope, said envelope proportioned to attain a minimumtemperature at any area of its inner walls of about 250 C., and means tosupply in said envelope an atmosphere of elemental iodine vapor of atleast about 15 milligrams per cc. of envelope volume and suflicient toproduce a luminous pulsating colored flame effect in the inclinedenvelope upon energization of the filament.

4. An electric incandescent lamp comprising a sealed envelope ofessentially tubular form adapted for orientation in a position inclinedfrom the horizontal during operation of the lamp, an incandesciblefilament having at least a significant portion thereof located at thebase of said envelope, said envelope proportioned to attain a minimumtemperature at any area of its inner walls of about 250 C., and means tosupply in said envelope an atmosphere of vapor of iodide of at least oneof the metals mercury, gold, zinc, tin, arsenic, antimony, bismuth andlead in an amount of at least about 15 milligrams of iodine content percc. of envelope volume and sufficient to produce a luminous pulsatingcolored flame efiect in the inclined envelope upon energization of thefilament.

5. An electric incandescent lamp comprising a sealed envelope ofessentially tubular form adapted for orientation in a position inclinedfrom the horizontal during operation of the lamp, an incandesciblefilament having at least a significant portion thereof located at thebase of said envelope, said envelope proportioned to attain a minimumtemperature at any area of its inner Walls of about 250 C., and means tosupply in said envelope an atmosphere of the vapor of mercuric iodide inan amount of at least about 15 milligrams of iodine content per cc. ofenvelope volume and sufficient to produce a luminous pulsating coloredflame effect in the inclined envelope upon energization of the filament.

6. A lamp as set forth in claim 1 wherein the envelope also contains afilling of nonoxidizing gas.

7. A lamp as set forth in claim 1 wherein the envelope also contains afilling of hydrogen gas.

8. A lamp as set forth in claim 3 wherein the lamp also contains afilling of hydrogen gas.

References Cited FOREIGN PATENTS 952,938 3/1964 Great Britain.

JAMES W. LAWRENCE, Primary Examiner.

S. A. SCHNEEBERGER, Assistant Examiner.

